WHY GO FOR A WALK? Not to get anywhere; the lack of destination makes it a walk rather than a journey. But a walk is never aimless; you set limits even before you start out: “as far as the woods,” “around the lake,” “along the river to the bridge and back.” Expediency determines the structure of a journey; on a walk you impose your own.

A walk offers a chance to check up on nature, to give in to your senses. You can take your self along for company, or leave it behind, depending on your mood. You can take the dog—an ideal arrangement, since your separate amusements don’t intrude on one another. It’s usually a mistake, as William Hazlitt has said, to go with a friend. Chatting turns the walk into a visit, and miles roll by without your once managing to come in touch with the sensibility of walking.

A walk is an abstraction, an idea. It is a particular kind of passage through space and time;